Ben Finney wrote: > [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote: > > def add(x, y): > > if x == 0: > > print y > > return y > > else: > > x -= 1 > > y += 1 > > add(x, y) > > To add to the other good advice in this thread: > > This is just one of many reasons why I advocate always having a > *single* return statement, at the *end* of the function. I usually > start out writing my function setting a default return value, and the > return statement immediately below. > > In your case, the default return value is None, so let's make that > explicit. > > def recursive_add(x, y): > result = None > return result > > Then, the rest of the function's responsibility is about changing that > default value if necessary. > > def recursive_add(x, y): > result = None > if x == 0: > print y > result = y > else: > x -= 1 > y += 1 > recursive_add(x, y) > return result > > With this structure, it becomes quickly obvious what's gone wrong: one > of the branches is not changing the default return value. > > def recursive_add(x, y): > if x == 0: > print y > result = y > else: > x -= 1 > y += 1 > result = recursive_add(x, y) > return result > > I find this much less error-prone than hiding return statements in > branches throughout the function; if the only return statement is at > the very end of the function, it becomes much easier to read.
I don't see this as clearer than multiple return. But then it I believe it is really preference or style, rather than obvious advantage/disadvantage. Interestingly, this kind of error is easy to spot by the compiler in C. -- http://mail.python.org/mailman/listinfo/python-list
